Well apparatus



N, K. SMITH WELL APPARATUS June 4, 1929.

3 Sheets-Sheet 1 Filed Nov. 8, 19,25

IIIII v luy W/ Il Nelson K. ML

A TTORNE YS- June 4, 1929. N, K. SMITH I 1.715576 WELL APPARATUS Fil'ed Nov. 8, 1926 3 Sheets-Sheet 2 A TTORNE YS.

N. K. SMITH WELL APPARATUS June' 4f,v 19291.

Filed Nov.- 8, 1926 5 Sheets-.Sheet 3 INVENTOR. Nelson KSmi/l TTORNEYS.`

Patented June 4, 1929;

UNITED aussie NELSON K. SMITH, OF LOS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- :MENTSJ TO THE GUIBERSON CORPORATION, OF DALLAS, TEXAS, A CORPORATION or DELAWARE.

WELL APPARATUS.

Application led November 8, 1926. Serial No. 146,975.

' 10 ment of introductlon of the string of tubing within the -well casing. The present catcher is so organized that it will operate automatically While the string of tublng is being lowered in the well, while it is in position in the .15 Well, and while it is being withdrawn from the well. In advertent or accidental drop of the tubing, or severance thereofat a pointV above the tubing catcher, will cause the automatic action of the catcher for its engagement with the well casing so as to check descent of the tubing after a momentary drop, and thus prevent damage or destruction to the string of tubing or the well inself.

In accordance with the present invention,

means are provided whereby the catcher may be voluntarily operated to cause the string of tubing to be locked Within the well casing, and the string of tubing may be readily Withdrawn from the casing after such voluntary locking operation.

The invention hasfor its objects the provision of an improved catcher or well apparatus of the general character stated which will be superior in point of relative simplicity and inexpensiveness of construction; taken in conunction with durability, reliability, length of ife, ositiveness in action and generalserviceabllity, and which will be generally superior in point .of eiciency.

With the above and other objects in view, the invention consists in the novel and use- Y ful provision, formation, combination, association and relative arrangement of parts, members and features, all as hereinafter described, shown in the drawings, and finally pointed out in claims.

In the drawings:

Figure 1 is a fragmentary elevation of a string -of tubing incorporated in which 'or applied to which is a catcher constructed and organized to embody the present invention, the same being shown surrounded by a section of well casing;

Figure 2 is a fragmentary elevation simllar tothat in Figure 1, with the parts slightly axially rotated, parts being shown broken catcher to lock the tubing against descent in the well casing, the parts shown in Figs. l, 2,

3 and 4 being shown with the catcher parts.

unlocked, or so that the string can descend;

Figure 6 is a view similar to Fig. 4, showing, however, the parts of the catcher in' posltlons consequent upon the initiated drop of the tubing, which has caused the automatic action of the catcher to prevent further drop;

Figure 7 is an enlarged detail sectional view, with parts-further in section, showing certain ofthe features shown in Fig. 6;

Figure 8 is a bottom 'end view of one of the sliding' collars, separated by the coil spring shown in the, other figures, the same being upon the -scale ofFig. 5;

`Figure 9 is a fragmentary vertical sectional view of certain features of the catcher shown in the other figures and includin the lower sliding collar and a portion o -the coil spring bearing downwardly thereupon, y

together with a portion of the rein of one of the catcher slips, the said lower sliding collar being in its lowermost position;

Figure 10 is a similar view, with further features, showing the said lower sliding collar in elevated position; o

Figure 11 is a detail transverse sectional View taken upon the line 111-11 Fig. 3, and looking in the direction of the appended ar-4 rows;

Figure 12 is a detail transverse sectionalV view, taken upon the line 12-12, Fig. 3,/and

loo'

looking in the direction ofthe appended arrows- Figure 13 is an enlarged detail transverse sectional view, taken upon the line 13-13, Fig. 2, looking as directed by the arrows;

and,

Figure 14 is a detail transverse sectional and upon which are formed ways .16, which are upwardly and outwardly inclined, and with which co-act slips or dogs 17 adapted to co-aet with such collar 15 and the string of tubing on the one hand, and the well casing 18 on the other hand, in order to lock the tubf ing and well casing togetherfand prevent descent thereof. C designates generally means for voluntarily or manually causing such locked relation, in order to lock the string of tubing in the well casingat any point and at any time desired;.and D designates means for automatically actuating the tubing catcher to cause such locked inter-relation between the tubing and the casing. Such means 'D are constructed and organized to operate upon an inadvertent or accidental drop or lowering of the string of tubing resulting from failure of the elevator or other means suspending the string of tubing at the 'mouth of the well, or upon a breaking of t-he string of tubing, as by the failure of the collar connecting adjacent joints thereof, or otherwise. The slips 17 are adapted to move vertically in the ways 16, and outwardly when raised and inwardlywhen lowered, and to such endsare respectively directly actuated by feet 17 a depending from the slips, and reins 17b rising from the slips. The feet 17 a, following the general teachings of an earlier application for Letters Patent filed by me January 18, 1926, Serial No. 82,085, for tubing catchers, normally depend within vertical slots 19 or. spaces between prongs 20 rising from a collar 21 loosely surrounding the tubing joint A, and joined with a similar loose collar 22 by outwardly bowed friction springs 23 having flattened faces frictionally engaging with the inner surface of the well casing 18. These prongs 20 rise within a centering collar 24 surrounding the Vtubing joint A and rigidly suspended vfrom the coupling 15,\such centering collar having a slotted or interrupted annular bead 'or rib 2lial slightly spaced from the inner wall of the well casing 18, andro-aeting with a further spacing collar 25 threaded upon the tubing joint B above the other features of the tubing catcher, to center the tub ing and the catcher within the well casing,

so as to properly present to the casing the `featureswhich co-aet therewith in a proper balanced relation. The centering collar 25 is likewise'provided with a vertically slotted bead or rib 25a which directly co-acts with the well casing in coordination with the bead or rib 24 of the centering collar 24. The vertical slotting or notchingof the beads or ribs permits the lowering of the tubing and tubing catcher through Huid in the well casing. A col-lar or coupling 26 upon the tubing joint A, or between it and the next lower tub ing joint, serves to limit downward movement of the sliding collar 22. lVhcn it is desired to manually or voluntarily actuate the slips 17 upwardly and outwardly to set the string of tubing in the well casing and lock it in position against further descent, it is only necessary to pull the string-of tubing upwardly, raising the feet 17a which depend from the slips, rotating the tubing slightly clockwise, looking downwardly, whereupon the feet 17a will be brought to rest upon the prongs 20; and when the string is' again permitted to. exert its downward thrust the bowed springs 23 will hold collar 21 and the prongs 20 relatively stationary, whereupon the ways 16 will be lowered and the slips 17 thrust upwardly and outwardly into positions such as shown in Figure 5, wherein they are wedged effectively between the ways and the well casing and, due to their transversely serrated outer surfaces, as shown at 17e-they are caused to bite into the casing, with their downwardly and outwardly-presented serration edges, effectively locking the tubing to the casing to prevent further descent of the former. In order to unlock the tubing from the casing it is only necessary to `pull up upon the string, whereupon the ways 16 travel upwardly along the inner faces of the-slips, and the slips become released from their locked positions.. If it is then desired to lower the string further, the tubing when elevated slightly, is turned counter-clockwise looking downwardly to bring-the feet in registration with the slots 19, whereupon the string may then be lowered and the feet will enter the slots 19, and the prongs bearing upv against the lower end portion of the collar 15 will be forced downwardly, also forcing downwardly the sliding collars 21 and 22 with the bowed springs connecting the same, and overcoming" the friction between said springs and the well casing.

The rein 17b of the slips 17 rise through slots 16a the tops of thel ways `16, and at their upper ends are bent into hooks 17d which enter radial openings 27 in the lower end portions of spaced fingers 28 in the slip actuator y E, which .loosely and slidably surrounds the tubing joint B to accommodate within the v same other parts to be specified. These fingers 28 loosely interlock with upwardly rising fingers 29 upon the collar 15, maintaining such collar 15 and slip actuator in rotative couple, so that at all times the slip actuator is in position to actuate the slips 17, in vertical direction. Thehooks 17d'are inwardly directed so that their outer end portions are directed outwardly through the openings 27. Slidably mounted upon the tubing joint B within the slip actuator E are upper and lower adjustable tension collars 30 and 31, which may each be reversed endrfor end, the collar 30 having, as shown positioned in the drawings, and particularly Fig. 3, an upperzportion 30a of lesser outside diameter and a lower portion.30b of greater outside diameter; and the lower adjustable tension collar 31, as p0- sitioned in Figure 3, having an upper portion 31'? of relatively greater outside, diameter and a lower portion 31b of relatively smaller out.- side diameter. These upper and lower portions in each instance onlyvextend part way about the collars, as clearly shown in Figs. 4 and 8. vThese limited portions of the collars are slidably mounted in slots 32 formed in the slip actuator E, through which slots also play outwardly bowed elongated friction springs 33, havlng at their lower ends hooks 33*L takinginto the openings 27 and having at their upper ends hooks 33b rest-ing upon the -upper end ofthe upper adjustable tension collar 30. These springs 33 bear frictionally against the inner wall of the well casing 18'. These springs partially sustain the weight of the slip actuator E, Between the tension collars 30 andl 31 a coil compression spring 34 surrounds the tubing joint B bearing upwardly upon the tension collar 30 and downwardly upon'the tension collar 31; and in accordance with the adjustment of saidcollars and the end o f which is uppermost each instance,

' exerting a .tendency to a greater or lesser extent to cause frictional engagement of said bowed springs 'with the inner surface of the well casing.

The collar 25 serves to lim-it the upward play of thel sli actuator E and prevents'disv placement of t e slips 17 from the ways 16.

Taking up'now the mode of4 operation of the l device as4 an entirety, it will be understood that the string of tubing withA the catcher elements and features are introduced'within the well casing 18 with the feet 17 a on the slips accommodated in the spaces 19 vbetween the vprongs 20. The'slips are therefore 1n the lowered positions .as shown in `Figures 1 to 4 inclusivel of the drawings. This condition is "maintained by the-slip actuator E the gravi-- tational eii'ect of which is slightly greater than the frictional'retardation of the bowed springs 33. It is'to'be stated in this connection that the downward and inward positioning of these slips -under the'predominat'- 'dropped in entirety,

actuator E when they are in normal lowered condition as shown in Figures 1 to 4 inclusive. The feet 17a pass through these bores. The coil spring 34 is in its maximum compression during the introduction of the tubing and attendant features in a well casing, and during the lowering of the same within the casing to the desired level in the hole.. The exert1on of this compression of the spring 34 causes maximum spacing apart of the collars 30 and 31 and causes one or more of the enlargements of the two adjustable tension collars 31 and 30 to bear against the bowed springs 33 jadjacent either the bottom or the top of each thereof or against both bottom and top, in accordance witlfthe adjustment of such collars, and their position upon the tubing. This causes the operative minimum friction of the bowed springs within the well casing for any given period of introduction and lowering of the tubing in the casing.

The action of the 'adj usting collars 30 and 31, p

under this maximum compression of the coil spring 34, is to cause a Hattening of the bowed formations of the springs 33, so as to produce the said minimumfrictionof said springs upon the well casing. If, now, the tubing is as by failure of support at the mouth of the well, or a fracture or severing of the tubing takes place above the tubing catcher elements, hitherto under its maximum com tends to expand. This is permitte falling of thetubing with its collar 15 ression, by the within which is formed a seat 15c against which thev lower portion of the collar 31 has rested during the lowering 'of the tubing and catcher. In other words, the shoulder 15 falls away from the collar 31, permitting the forcing down of said collary 31 by the spring 34. As the spring 34 relaxes in its compression the upward pressure of the collar 30 against the upper ends ^of the bowed springs 33 is relaxed, permitting such springs to assume va more pronouncedly bowed formation, thus increasing the friction thereof within the well casing. Thus, the maximum friction of .ation of the device is set up, and this maxiin'g weight of the slip actuator'E is assisted by downwardly and inwardly inclined bores 15 in keepers 15",;provided at the lower end of the coupling or union 15. The keepers 15b arebeveled off at their top surfaces, as a't 15d,

' and the slips 17 are similarly chamfered or beveled as at '17d to fit and coact with said beveled portions. 15d of the keepers to primamum friction'arrests the slip actuator E in lts fall 1n company with the string and other features, setting up a differential between the spring 34,

ythe bowed springs for any given use and operl .such rate ofpfall and the Vrate of fall of the tubing. The resultof this differential component is to likewise arrest the slips 17 in their? participation in the common fall of parts and elements, so that a differential isA set up betweenthe rate of fall ofthe slips and the rate of fall of the tubing with its collar 15 and the slip-ways 16 thereon, and the slip-' ways wedge the slips outwardly into the positions shown in Figures 6 and 10, wherein jthey arrest further fall of the tubing andassociated parts. When it isdesiredtnow to withdraw the tubing from within the casing it is only necessary to pull upwardly on the string, whereupon the tubing becomes freed from the casing by the release of the slips, the ways riding upwardly within the group of slips,`and the slips thus retreating from the casing in relative downward and inward motion. All of the parts which have to; do with the automatic action described, including the spring 34 and bowed springs 33 and collars and 31, then assume their normal conditions and positions and the string may be again supported or suspended within the casing for further autonatic action, unless it is necessary to perform a fish-ing job and remove the whole string. The slip actuator E has a lip e overlapping .the collar 30.

It will be obvious, due to the well-establibcd mechanical equivalence of a spring and a weight., that the catcher device may be modiiied, aside from other considerations, by eliminating the upper adjustable tension collar 30, together with the coil spring 34, and utilizing merely the adjustable tension collar 31 or the equivalent, as primarily a weight, to act` upon `the friction of the springs or bowed springs 33 upon the drop of the tubing string and the lowering of such collar 31 or its equivalent permitted by the resultant drop of the collar or union 15. In this case, the upper end of the springs 33 could be riveted to the slip actuator member E,at the upper portion thereof. This is such an obvious modification, within the doctrine of mechanical equivalence, that it is not deemed necessary to separately illustrate it in the drawings.

At no time in the operation of this device are the slips or dogs poised upon or sustained in a poised relation by the coil spring 34, and if desired the bowing of the springs 33 may be so adjusted and the parts sointer-related with such bowed' springs that the coil spring 34 may be eliminated.

I have already described the voluntary operation of the device in order to lock the tubing in the well casing by means of the slips ticing the invention, in departure from the (itl specific provision and construction and interrelation of parts, members and features here-.. .tofore described and disclosed in the drawing,

without departing from the true spirit of the invention.

Having thus disclosed my invention, I claim and desire to secure by Letters Patent: 1. In combination with a string of tubing or other structure adapted to be lowered in well casing;- slips, means upon the string orl other structure adapted to cooperate with the slips to cause the same to wedge against the well casing; means co-acting with .the slips and frictionally co-acting with the casing to permit the string or the like to be lowered with the slips i-n retracted position, and means for increasing the frictional action thereof upon a sudden lowering -of the string or the like; said friction means comprising a bowed spring. y

3. In combination with a string of tubing or other structure adapted to be lowered in a well casing; slips, means upon the string or other structure adapted to cooperate with the slip to cause the same, to wedge against the well casing; means co-acting with the slips and frictionally 'co-acting' with the casing to permit the string or the like to be lowL ered with the slips in retracted position, and means cooperating with said last named means for increasing the frictional action thereof upon a sudden lowering of the string or the like; there being aslip-actuator mov ably mounted in lconnection with said string or the like and with which'said slips or the like are connected., V

4. In combination with a string of tubing or other structure adapted to be lowered in a well'casing; slips, means upon the string or other structure adapted. to cooperate with the slips to cause the same to wedge against the well casing; means co-acting with the slips and frictionally co-acting with the casing to permit the string or the like to be lowered with the slips in retracted position, and means cooperating with said lastnamed means for increasing the frictional action thereof upon.

a sudden lowering of the string or the like; there being a slip-actuator movably mounted in connection with said string or the like and withl which said slips are connected; said friction means being mounted in connection with said slip actuator.

5. In combinatlon with-a string of tubing or other structure adapted to'be lowered in a well casing; slips, means upon the string or other structure adapted to cooperate'with the slips to cause the same to wedge against `the well casing; means co-acting with` the slips and frictionally co-acting lwith the anatre casing to 4permit the string orM the like t be f lowered with the slips in retracted position,

connected; said friction means being mount ed in connection with said slip actuator; the

weight of said slips and slip actuator minusv the moment of said frictional means being normally carried by the string orthe like.

6. In combination with a string of tubing or other structure adapted to be lowered in a well casing; slips, means upon the string or other structure adapted to cooperate with the slips tov cause the same to wedge a ainst the well casing; means co-acting cwit the slips land frictionally co-acting with the casing to permit the string, or the like lto be lowered withvthe slips in retracted "position, and means cooperating with said last named means for increasing 'the frictional action thereof upon a sudden lowering of the string or the like; said last named means including a movable member mounted in connection with said' tubing and normally supported thereby. l

7. In combination with a string of tubing o r other structure adapted to be lowered in a well casing; slips, means upon the string or other structure adapted to cooperate with the slips to cause the same to wedge against the well casing; means co-acting with the slips and frictionally co-acting with the casing to permit the string or thelike to be lowered with the slips in retractedA position, and means cooperating with said last named means for increasing the rictional action thereof upon a sudden lowering of the string or the like; said last named means including a movable member mounted in connection with said tubing and normally supported thereby; further means being provided urging said last named member toward its normally supported position. f

8. In combination with a string of tubing or other structure adapted to be lowered in a` well casing; slips, means upon the string or other structure adapted to coo erate with the slips to cause the same to we ge against the well casing; means co-acting with the slips and frictionally co-acting with the casing to permit the string or the like .to be lowered with the -slips in retracted position, and means cooperating with said last named means for increasing the fr'ictional action thereof upon a suddenv lowering of the string or the like; said last named means including a movable member mounted in connection with said tubing and normally supported thereby; further means being provided urging said last named member toward its normally supported position; and a further member movably mounted in connection with the tubing or the l1ke and between which and saidl 'named movable member said last named means is disposed.

9. In combination with a stringof tubing or other structure adapted to be lowered'in a well casing; slips, means upon the string or other structure adapted to cooperate with the slips to cause the same towedge against the well casing; means co-acting with the slips and frictionally co-acting with the casing to permit the string or the like to be lowered with the slips -in retracted position, and means cooperating with said last'named means for increasing the frictiona'l action thereof upon a sudden lowering of the string or lthe like; said last named means including a movable member mounted 1n connection with said) tubing 'and normally supported thereby; further means being provided urging saidlast named member toward its normally supported position; and a further member movably mounted in connection with the tubing or the like and between which and said first named movable member said lastnamed means is disposed; said last named means comprising a coilcompression spring.'

k10. In combinationpwith a string of tubing orother structure adapted to be lowered in a well casing; slips, means upon the string or other structure-adapted to cooperate with the slips to cause the same to wedge against the well casing; means 'co-acting with the slips and frictionally co-acting with the casing 'to permit the stringor the like to be lowered with the slipsin retracted position, and means cooperating with said last named means for increasing the frictional action thereof upon a sudden lowering of the string or the like; said last named means including a movable member mounted in connection with,v tubing and normally supported thereby fu ther means being provided urging said la,

named member toward its normally supported l "i Tlf.

position; and a further member movably mounted in connection with the tubing er the like and between which and said first named movable member said last named means is disposed; said last named means comprising a .coil compression spring; said frictional means comprising a bowed .s ring adapted to contact with the casing an spaced portions. with said first` and second named movable members.

11. In combination with a string v4of tubing or other structure adapted to be lowered in a well casing; slips, means upon the str ing or other -structure adapted to cooperate with the cooperating at.

-, slips to cause the same to wedge against the well casing; means co-actingfwith theslips and frictionally'co-acting with the casing to permit the string or the like to be lowered l with the slips in retracted position, and means asudden lowering of the string or the like; said last named means including a movable member` mounted in connection with said tubing and normally supported thereby; further means being provided urging said last named member toward its normally supported position; and a further member movably mounted in connection with the tubing 'or the like and between which and said first named movable member said last named v means is disposed; said last named means comprising a coil compression spring; said frictional means comprising a bowed spring adapted to contact with the casing and cooperating at spaced portions with said irst and second named movable members; one-of said movablev members having an enlarged portion adapted to decrease the bowed, formation of said spring upon`the abrupt lowering of the tubing or the like.

12. In combination with a string of tubing or other structure adapted to be lowered in a well casing; slips, means upon the string or other structure adapted to cooperate with the 'slips to cause the same to wedge against the f' Well casing; means co-actingwith the slips and frictionally co-acting with the casing to permit the string or the like to be ylowered with the slips in retracted position, and means cooperating with said last named means for increasing the frictional action thereof upon a sudden lowering of the string or the like; said last named means including a movable member mounted in connection with said tubing and normally supported thereby; further means being provided urgng said last ,named member; toward its normally supported position; and a further member movably mounted in connection with the tubingor the `like and between which and said first named movable member said last named `means is disposed; said last named means comprising a coil compression spring; Vsaid frictional means comprising a bowed spring adapted to contact with the casing and'cooperating at spaced portions with said first and second named movable members; one of said movable'members having an enlarged portion adapted to decrease the bowed formation of said spring upon the abrupt lowering of the tubing or the like; the other movable ,member likewise being provided with an enpermit the string or the like to be lowered with the slips in retracted position, and means cooperating with saidlast `named means for increasing the frictional action thereof upon a sudden lowering of the string or the like; said last named means including a movable member mounted in connection with. said tubing and normally supported thereby; further means being provided urging said last named member toward its normally supported position; and a further member movably mounted in connection with the tubing or the like and between which and said first named movable member said last named means is disposed; said last named means comprising va coil compression spring; said frictional means comprising a bowed spring adapted to contact with the casing and cooperating at spaced portions with said' first and second named movable members; one of said movable` members having an enlarged portion adapted to decrease the bowed formation of said spring upon the ...abrupt lowering of the tubing or the like ;the other movable member likewisebeing provided with an enlarged portion and being adjustably mounted so that it may be reversed end for end upon said tubing; the other movable member being likewise reversable and having a second and more extensively enlarged portion. Y

14. I n a device of the character disclosed, a string of tubing or the like adapted to be lowered in well casing, a 'slip or the like, means upon the tubing-or the like to .co-act with said slip or the like to cause wedge action of the slip between the casing and the tubing; friction means for cooperating with the casing and the slip and normally permitting the slip to occupy a retracted position, and means movably mounted in connection with the tubing for increasing the action of said frictional means upon a sudden lowering of the tubing.

15. In a device of the character disclosed, a string of tubing or the like adapted to be lowered in well casing, a slip or the like, means upon the tubing or the like to co-act with said slip or the like to cause wedge action of the slip between the casing and the tubing; friction means for cooperating with the casing and the slip andnormally permitting the slip to occupy a retracted position, and means movably mounted in connection with the tubing for lincreasing the action of said frictional means upon a sudden lowering of the tubing; said frictional means comprising a normally bowed spring, and said movably mounted means cooperating with A said spring to increase the frictional moment thereof.

16. In a device of the character disclosed.VA

Maaate of said frictional means upon the sudden lowering of the tubing; said frictional means comprising a normally bowed spring, and said movably mounted means cooperating with said spring to increase the frictional moment thereof; and a slip actuator with which said spring co-acts and which slip actuator is connected with said slip.

17. In a device of tlie character disclosed, a string of tubing'or the like` adapted to be lowered in well casing, a slip or the like,

means upon the tubing or the like to co-act with said sli or the like to cause wedge action of the s ip between the casing and the tubing; friction means for cooperating with the casing and the slip a'nd normally permitting the slip to occupya retracted position, and means movably mounted in connection with the tubing for increasing the action of said frictional means upon the sudden lowering of the tubin said frictional means comprising a normallyl bowed spring, and said movably mounted means cooperating with said spring to increase the frictional Inoment thereof; and a slip actuator with which said spring co-acts and which slip actuator is connected with said slip; said means upon the tubing comprising a slidable member normally carried by the tubing and permitted to fall independently of the tubing upon abrupt descent of the tubing.

18. -In a device of the character-disclosed, a string of tubingor the like adapted to be lowered in well casing, a slip or 'the like, means upon the tubin or the like to co-act with said slip or the like to cause wedgeacc tion of the slip between the casing and the l tubing; friction means forcooperating with 4the casing and the slip and normally permitting the slip-to occupy a retracted position, and `means movably mounted in connectien with. the tubing for increasing the action of said frictional means upon the sudden loIwyering of the tubing; said frictional means comprising a normally bowed spring, and said movably. mounted means. cooperating with said spring to increase the frictional moment thereof; and a slip actuator with which said spring co-acts and'which slip actuator is connected Wittsaid slip; said mans upon the tubing comprising a slidable member normally carried by the tubing. and permitted to fall independently of the tubing upon abrut. descent of the tubingrmeans .for norma ly urging said last named` and v y supported by the tubing.

means toward the position in which itlis 19. Inf a device of the character disclosed, the cbmbination with a string of tubing or the like/,adapted to be lowered in a well casing, a slip or the like adapted to cooperate withl the tubing or the like to beiwedg'ed bei the combination with a strin of tubing or the like adapted to be lowere in a well casing, a slip or thelike adapted to cooperate with the tubing or the like to be wedged between the tubing or the like and the casing; frictional means adapted yto co-act with the casing and the slip to^ permit the gradual lowering of the tubing with the slip in retracted position, and means 'mounted in connection with the tubing for increasing the frictional coeiiicient of said last named means' upon an abrupt drop of the tubin to cause the slip to wedge between the tu ing and the casing; said last named means being normally carried by thetubing and freed therefrom to fall independently of thel tubing upon an abrupt drop of the tubing. t

21. In a device of the character disclosed, the combination with a string of'tubing or the like adapted to be lowered in a Well cas-- ing, a slip or the like adapted to cooperate with the tubing or Athe like to be wedged between the tubing or the like and the casing; frictional means adapted to co-act with the casing and the sli lowering of the tu ingA with the slip in 'reto permit the gradual tracted position, and means mounted in conthe combination with a Astrin of tubingvor the like adapted to be lowere in a well casing, a slip or the like adapted to cooperate' with the tubing or the like to bewedged between the tubing or the like and the casing;

frictional meansfadapted to co-act with the /casingand the slip to permit the gradual lowering f the tu i tracted position, and means mounted in con-w nection'with the tubin for increasing they' frictional moment of said last named -means upon an abru t drop of the tubing to cause the slip to we ge between tle tubing and the easing; said last named means being nor- `tional means comprisin a normally bowed mally carried by the tubing and freed therespring one portion of W ich rests upon said from to fall independently of the tubing upon last named means; whereb upon an. abrupt an abrupt drop of the tubing, and spring drop of the tubing said bowed spring is 5 means actingin connection with said last caused at its upper portion to be `flexed to- 15" named means; said slip normally resting ward a more bowed position. u on said tubing independent; of the action In testimony whereof, I have signed my 0i) said spring means; further means mountname to this specification. ed movably in connection with the tubing 10 and above saidspring means; and said fric- NELSON K. SMITH. 

